Condition factor, growth performance, and production of Rainbow trout (Oncorhynchus mykiss) in floating cages in a shallow reservoir in Panauti, Nepal: A preliminary study

Abstract

Rainbow trout (Oncorhynchus mykiss) is getting priority in aquaculture in Nepal. However, high investments, slow growth in land-based/raceway systems are major challenges. Country would be benefited, if lakes/reservoirs could be utilized for its cage culture. A preliminary trial was conducted in a shallow-reservoir created for hydropower installing three cages, 6 m × 4 m × 2 m size to evaluate its growth and production potential. The trout juveniles of 57.6±15.4 g (average weightSD) were stocked and fed with 33% crude protein diet twice daily at maximum 3% of body weight for 91-days. A random sample of 50 fish per cage was measured total length and body weight each month. Results showed that it is possible to achieve high survival (96.61.7%) with reasonable growth rate (0.80 g.fish -1 ) and productivity (8927 kg.cage -1 ) with fair condition factor (1.20.1) when stocked 10-20 fish.m -3 . These parameters implied that farming of rainbow trout in the shallow reservoir could be successfully done during winter-spring season in a year. However, further research is needed with stocking densities, feeds and feeding rates/methods, and also conducting longer period which may further enhance the productivity thereby profitability.